It is well known that a machine, such as a backhoe loader, is used to dig ditches, foundations, basements, and the like. During such machining operations, the backhoe loader machine utilizes a pair of stabilizer legs to maintain a steady and solid working foundation. The foundation is established when the pair of stabilizer legs are extended either individually or together by separate and continuous activation of a pair of control switches. Each one of the pair of control switches is coupled with a respective one of the pair of stabilizer legs and the amount of stabilizer leg extension depends on the surrounding terrain. Generally, upon completion of machining operations, the pair of stabilizer legs are retracted through the separate and continuous activation of the pair of control switches. The ability to retract both of the stabilizer legs simultaneously without continuous operation of the pair of control switches, however, would be beneficial for an operator due to an ease in operation.
A design disclosed in U.S. Pat. No. 4,124,226 issued to Frank T. Phillips on Nov. 7, 1978 utilizes four hydraulically operated outrigger assemblies on a mobile crane. A control system is provided for operating the eight cylinders to extend, retract, and lower and raise the outriggers through actuation of horizontal and vertical stabilizer cylinders, respectively. Simultaneous extension or retraction of the outrigger assemblies is achieved by the continuous operation of various switches in combination. Unfortunately, the ability to simultaneously retract the outrigger assemblies through a single switch that does not require continuous operation is not disclosed. The ability to simultaneously retract the outrigger assemblies in such a manner would improve operator flexibility by lessening the time and energy normally spent on retracting the outrigger assemblies.
The present invention is directed to overcoming the problems as set forth above.
In one aspect of the present invention, a method is disclosed for automatically retracting a stabilizer leg for a work machine. The work machine is operatively associated with a power source and has a control device for selecting forward or reverse directions of movement. The method includes utilizing a control lever for moving the stabilizer leg between fully extended and fully retracted positions. The control lever is normally located in and biased to a neutral position. Next, manually moving the control lever to either of an extend position or a retract position. Then, manually holding the control lever in either of the extend or retract positions to respectively extend or retract the stabilizer leg to any of a plurality of desired positions between the fully extended and fully retracted positions. Next, manually moving the control lever to an auto-retract position. Finally, retaining the control lever in the auto-retract position without further manual manipulation thereof through a responsive means that overcomes the biasing action of the control lever to facilitate the automatic retraction of the stabilizer leg from any of the plurality of desired positions to the fully retracted position.
In another aspect of the present invention, a work machine has front and rear end portions. A control panel is disposed within an interior of the work machine. A pair of stabilizer legs are connected to the rear end portion. A hydraulic cylinder is operatively associated with each of the pair of stabilizer legs for moving the stabilizer legs in a plurality of desired positions between fully extended and fully retracted positions via a source of hydraulic fluid. A control device is located within the interior of the work machine for selecting the forward or reverse direction of the work machine. The present invention comprises a main valve that is connectable with each of the hydraulic cylinders for controlling the movement of the stabilizer legs. A pair of pilot valves are in connection with each of the main valves. A pair of control levers are in connection with a respective pair of pilot valves for actuation thereof. The control levers are normally biased to a neutral position and movable between a first position for actuating the main valves in response to the actuation of one of the pilot valves to extend the stabilizer legs to any of the desired positions, a second position for actuating the main valves in response to the actuation of the other of the one of the pilot valves to retract the stabilizer legs to any of the desired positions, and a third position. Means are provided for automatically retaining the pair of control levers in the third position for actuating the main valves in response to the actuation of the other one of the pilot valves to simultaneously retract the stabilizer legs from any of the desired positions to the fully retracted position within a preselected period of time.
In yet another aspect of the present invention, a method is disclosed for automatically retracting a stabilizer leg for a work machine. The work machine is operatively associated with a power source and has a control device for selecting forward or reverse directions of movement for the work machine. The method comprises the steps of utilizing a pair of control levers for moving a pair of stabilizer legs between fully extended and fully retracted positions. The control levers are normally located in a neutral position and movable to first, second, and third positions. The movement of either of the control levers to the first position promotes the movement of a respective stabilizer leg to a plurality of extended positions and the movement of either of the control levers to the second position promotes the movement of the respective stabilizer leg to a plurality of retracted positions. The control levers are biased to the neutral position when in the first, second, or third positions. Next, the method includes moving either of the control levers to the third position. Finally, automatically maintaining either of the control levers in the third position to overcome the biasing action on the control levers for moving the respective stabilizer leg from any of the plurality of extended or retracted positions to the fully retracted position.
The present invention includes the ability to simultaneously retract a pair of stabilizer legs for a work machine through a control lever that is automatically retained in a auto-retract position for a preselected time. The simultaneous and automatic retraction of the pair of stabilizer legs increases ease of operation and operator flexibility.